Roadblocks to Zero-Energy Homes

In order to reach zero energy, a new home will require at least $20,000 worth of PV capacity just to offset the consumption of miscellaneous devices!

On the whole, houses in the United States are better insulated and have more efficient HVAC and domestic hot water systems than ever before. This is especially true for homes built to Energy Star and other efficiency and green building standards. But as homes become more efficient at heating, cooling, and making hot water, other energy uses in the home that had largely been ignored in the past come to the forefront. Today, major appliances use approximately 25%, lighting uses approximately 20%, and miscellaneous equipment uses about 15% of a home’s electricity. Nationwide, these end uses account for about 40% of total residential primary (or “source”) energy consumption. Moreover, miscellaneous energy is the fastest-growing end use in U.S. homes; it is projected to more than double in the next 20 years. This is particularly true in new homes, where increasing floor area and added amenities require more electricity for lighting, electronics, and other plug load devices. And while new homes have long been the subject of programs and policies to reduce energy use, these programs have focused almost exclusively on traditional end uses. (Notable exceptions are California’s Title 24 building standard, which includes requirements for lighting efficiency, and the ...